Process for coking carbonaceous material



Feb. 2, w43. c. H. HUGHES 2,309,959

PROCESS FOR COKING CARBOANACEOUS MATERIAL original Filed oct. 25. 1939 ssheets-sheet 1 ATTORNEY Feb. 2, 1943.

c. H. HUGHES 2,309,959

ROCESS FOR COKING CARBONACEOUS MATERIAL Original Filed Oct. 25, 1939 8Sheets-Sheet 2 Mw -BY ATTO RN EY Feb. 2, i943. C H. HUGHES 2,309,959

PROCESS FOR COKING CARBONACEOUS MATERIAL Original Filed Oct. 25, 1959 8Sheets-Sheet 3 gw/2R @L @im ATTORN EY Feb., 2, 1943. c. H. HUGHES2,309,959

PROCESS FOR COKING CARBONACEOUS MATERI'AL Original Filed Oct. 25, 1939 8Sheecs--Sheeb 4 ATTORN EY Feb. 2, 1943. c, HUGHES 2,309,959

rnocsss Foa coxmG cARBoNAcEous MATERIAL Original Filed oct. 25, 19:59 8sheets-sheet 5 ATTORNEY Feb. 2, 1943. c. H. HUGHES PROCSS FOR COKINGCARBONACEOUS MATERIAL Original Filed OCT.. 25, 1939 8 Sheets-Sheet 6,EZ/W

ATTORNEY.

Feb.'y 2,'1943. C. H'. HUGHES 2,309,959

PROCESS FOR COKING CARBONACEOUS MATERIAL Original Filed Oct. 25, 1939 8Sheets-Sheet '7 ATTORNEY Feb. 2, 1943. c. H. HUGHES PROCESS FOR GOK-INGCARBONACEOUS MATERIAL Original Filed Oct. 25, 1939 8 Sheets-Sheet 8ATTORNEY Patented Feb. 2, 1943 PROCESS FOR `COKING CARBONACEOUS MATERIALCharles H. Hughes, Glen Ridge, N. J., assignor to Hughes By-Product CokeOven Corporation, New York, N. Y., a. corporation of New York originalappucation october 25, i939, serial No. 301,173. Divided and thisapplication March 1,

1941, Serial- No. 381,358

' 4 Claims.

The present invention relates to a process forl coking carbonaceousmaterial and, more particularly, to a process for coking coal. Y

It is well known by those skilled in the art that in the earliest timescoke was. produced in moundshaped Mailers similar to the old method ofburning charcoal in heaps. 4The beehive oven was a modication of these,except that it was built of brick instead of sod or clay, and theearliest record of coking coal in a regular oven is an English patent toSt. John granted in 1620 for making coke in a beehive form of oven.Although a German chemist, Becher, received a patent in 1700 yforrecovering tar from coking coal, it appears that it was not untilClaytons discovery in l 1737 that the formation of a combustible gaswhen coking coal was noticed. About the year 1767, a form of coke oven,producing coke and recovering some tar and ammonia, was constructed inGermany and was described as a domelike lire clay retort. In 1781, anattempt appears to have been made to recover the by-products, and apatent to the Earl of Dundonald was issued, and in 1792 Murdochexperimented with. making gas from coal in retorts. These efforts borefruit, and twenty years later the streets of London were lighted by gas.

The earliest records of the rectangular, or retort, ovens show them inoperation in Germany about i830. They had open walls, pierced byhorizontal and vertical liues, and the walls formed a rectangular spacewhich contained the'charge. in 1856, Knab is reported to have built agroup of retort coke ovens to recover lay-products and illuminating gas.These ovenshad nues on the bottom only, but of course, no regenerator orrecuperator system was provided. Moreover, there was no attempt tofurnish uniform heating to the oven sole, the re or :llame passing froma grate through a central flue and then returning through the nues onboth sides thereof. -The following year, Appolt built his first ovens inthe shape of vertical and, later, horizontal retorts, using his gas onlyfor heating his oven through horizontal nues. This was about theearliest `closed retort coke oven, utilizing the gas for its ownheating. By 1861 the Coppee coke oven 'of Belgian invention was in useon the Continent, and in 1873-74 it was introduced into England. It hadvertical flues and was of the non-recovery type.

About 1862 Carves of France introduced side ues in addition to thebottom liues of Knab. About 1880, Simon, an English inventor, improvedthe Carves oven very materially by adding recuperating nues. -Thls ovenhad the oven oven.

nues placed horizontally, the gas and air Ibeing first 4burned in soleflues located underneath the oven chambers, then passing up through ariser to the ovens and down through three horizontal tlues in series. Inthe years 1881 to 1883, Seibel patented an oven having horizontal iiuesand having neither grates4 nor regenerators. It is apparent that ovendesigns up to this time were so uneconomical of gas used in heating theovens, or the coals were so lean in gas, that grates for burning coalwereV built into the ovens and the gas was nrst admitted over thesegratas, the amount of coal being such as to supply the requiredadditional heat.

The lirst ovens oi' the Otto type had been erected in Germany in 1881,and in the same year Huessner appropriated the Knab-Carves model andbuilt a hundred ovens in Germany, thus establishing the industry on asound basis in that country, although the quality of coke from theseovens was inferior. In these ovens the nues were horizontal. A verysubstantial improvement was made by Hoffman, who added the Siemensregenerator to the Otto coke oven and thus provided the rst reallyeiilcient coke oven, generally reerred to in the art as the Otto-Hoffmancoke In 1888 Festner, a German inventor, changed the Otto-Hoffman designby using horizontal instead of vertical nues and abandoning the Siemensregenerators, replacing the same with a Ponsard gas furnace. Hoffmancooperated with Festner, and this design was called a Festner-Hoimanoven., having horizontal nues and recuperators. In 1887, theSernet-Solvay oven came into notice, the rst of them having norecuperators or regenerators. It appears that the principal features ofSemets design were the introduction of the division wall, the buildingof the oven ue system as a sleeve out of D-shaped tile, and the startingof the combustion at the top, or No. 1, flue, and, in general, providinga structure which was strong, easily heated and had well as underneath.

The high, narrow coke ovens of the prior art described in the foregoinghad various important disadvantages. For instance, a recent standar`dtype was usually of the order of about 45 feet in length, about 16 feethigh, and about 17 inches in width. and, because of its height andnarrowness, it had to be constructed and built in very large individualunits, so that the original cost oi' installation was extremely high.Generally speaking,` it was not possible either to build or to operaterelatively small units of the conventional type "at a low cost.

Besides these economic disadvantages, the use of a high, narrow oven waslimited to certain coals or coal mixtures. Coals which expanded uponco'king could only be used ii mixed with shrinking coals, as otherwisethe wear on the walls-was too great, and the increasing pressure mighthave led to destruction oi the ovens. Using a large percentage ofshrinking coals, as necessarily became general practice, the coal shrankaway from the heating walls, causing the formation between. coke andwall of irregular gaps and crevices which acted as channels for thegases distilled.' from the coal. Due to the irregularity oi thesechannels, heat could not be y.

applied so as to produce a uniformly carbonized coke in a short cokingperiod, regardless of the `inethod of heating or control employed.

' siderable heat from reaching the charge by conduction. Again, thegases, being much lower in temperature than the walls, took upconsiderable heat from them and thus prevented this amount of heat fromreaching the core of the charge at all. Botlrof these e-lects resultedin greatly retarding the coking time and were diametrically opposed tothe results desired, for it was, of course, the purpose of the operationto transfer heat from walls to coal charge as eiliciently as possibleand in the shortest time. Moreover, the

heating oi' the gases had the undesirable edect of passing the gases tothe icy-product plant in a super-heated state, necessitating largercondensing surfaces to cool them. p

A further disadvantage of the high narrow coke oven was that the widthof the charge varied over the length of the oven., for practical reasonsbeing smaller at the pusher end than at the coke discharge end. For thepurpose of providing uniform coking throughout this constantly varyingoven width, more gas had to be burned in the iiues at the coke end ofthe oven, necessitating a difference in size of heating ues over thelength of the oven. This required very accurate control of the fuel gasto the individual iiues.

Under these conditions, it was diiilcult to control heating conditionsin these ovens. the oven structure was intricate and expensive,resulting in high-cost coke, and the coke produced was primarilysuitable only for metallurgical purposes and not for domestic use.Subsequently, a broad rectangular sole-tired coke oven attempting to 7seliminate these disadvantages was developed, but other difiicultiesarose.

Essentially, this broad oven construction provided a rectangularsole-red coke oven having a multiplicity of long, independent, parallelheating ues arranged side by side, each of said fiues being directlyconnected at each end to two shallow, horizontal hair-pin regeneratorsbelow and parallel to and individual to each separate heating ilue foralternately supplying heatedA air to the flues and receiving the heat ofwaste gases discharged therefrom. Each heating flue was provided with aburner or means for supplying rich fuel gas to both ends thereof.

In this manner, all of the flames burned in independent fines, entirelyisolated from each other. These llames were all at one end of ,the longoven and extended in thel dirction of the other end, usually someforty-odd feet away. Burners were located at each end of the nues, andeach heating ilue and its associated regenerators could thus bealternately operated, independently of adjoining heating ues andregenerators.

It is particularly to be notedthat the oven described could be used withrich fuel gas only,

as no provision was made for preheating the fuel.

Since emcient operation with lean fuel gas required that it be preheatedbefore passing to the burners, it is obvious that this oven was limitedas to its source of heat. This raised a serious problem, as the pricesat which fuel gas could be bought or manufactured ductuatedconsiderably, and it was not at all unusual for the costs of lean andrich gas so to vary with resct to each other that they actually competedwith each other for a market. Operators could not take advantage of thiseconomic situation, of course, when they could not possibly employ thelean gas.

Although this conventional type of broad oven could be built inrelatively small units, the entire heating system and the so-calledregenerators employed were fundamentally incorrect. The oven wasdesigned for underflring with rich coke oven gas only. The use of cokeyoven gas with preheated air gave a shortand hot iiame resulting innonuniform heating of the lons. straight parallel heating flues. Anexcessively high temperature occurred at each burner, producing dangerpoints or hot spots. Moreover, the regeneratorswere so designed.l thatthe waste gas and incoming air always circulated in a horizontaldirection which failed to give satisfactory and eilcient results. Y

In other words, by eliminating some of the disadvantages of prior ovens,the broad oven described introduced new diiculties which were in partmuch more serious than the former. Thus, the ends of the heating lueswere overheated, causing overcoking and quick overheating of theconstruction material of the oven. The heat thus furnished in excess atthe ends of the fines did not, however, propagate itself in suiilcientamount along their length. The ilues were so long, running (as they did)the entire length of the oven, that black spots, too cold for propercokingfdeveloped at their centers. Clearly, it was practicallyimpossible to obtain proper coking of the center mass except, and thento only a small extent, by overcoking the masses at the ends, of theilues. While this defect was sought to be remedied by Zwillinger, whoput a division wall at the center to halve the flue length andsimultaneously burned flames at both ends of the oven toward this wall,this arrangement provided no real solution to the problem. It merelysubstituted for the oven-length flue a semi-ovenlength flue, still fartoo long for the ame to heat it properly.' There were still cold blackspots at the oven centers in the vicinity of the division wall.

` Then, too, the broad oven described did not provide adequate spaceabove and below the re.

generators in which the gases could spread or mushroom out before goingthrough the checkerbrick. Moreover, the regenerators, which wereindividual for each flue, were insufficient in size and could notfunction satisfactorily. The velocity `of the gases in the heating flueswas too low and in the regenerators too high for proper heat transfer.Of course, not only did this nonuniform distribution of heat greatlydecrease the over-all eiiiciency of these ovens, but, especially, thehot spots, developed in the operation of the oven, caused earlydeterioration of the building material and greatly increased the cost ofoperation and maintenance. Although these difficulties were well knownin the art, and, from time to time, various suggestions and proposalswere made to eliminate them, none of these suggestions and proposals, sofar as I am aware, was completely satisfactory and successful on apractical and industrial scale.

I have discovered that the outstanding problem may be solved in a simpleand completelyv satisfactory manner.

It is an object of the present invention to provide a process for cokingcarbonaceous material which eliminates the aforementioned diiiicultiesexperienced in the operation of conventional broad coke ovens.

It is another object of this invention to provide a process of cokingcoals, tars and oils to produce a coke substance with burningcharacteristics different from those'of coke produced heretofore byprior art processes.

It is a further object of the invention to provide a coking processwhich is easily adaptable to the coking of any carbonaceous material,such as coal, peat, tar, lignite, pitch, culm waste and other low gradecoals, fuel oil, bunker oils and other petroleum products, and the like.

It is also an object of the invention to provide a coking process forcoking ra broad iiat layer of coal to produce a coke of far greatersuitability for domestic purposes than that produced in the high, narrowwalls of the prior art.

The invention also provides a process for coking coal in a thin layer topermit the free iiow of hot evolved gases whereby an open cell structureresults.

The invention also provides a coking process wherein combustible gasesat a temperature sufficient to coke carbonaceous material are directedin a plurality of parallel streams beneath said material, transverselythereto and out of contact therewith, whereby substantially uniformcoking of said material can be obtained.

My invention -also contemplates the provision of a process for cokingcoal wherein either rich fuel gas or, alternately, preheated lean fuelgas can be employed as the fuel source for raising the temperature to apoint sufficient for coking the coal.

Other and further objects and advantages of the invention will becomeapparent from the following description taken in conjunction with theaccompanying drawings, in which:

Fig. 1 illustrates a sectional plan view of an oven embodying theprinciples of the present invention, taken on hline I-I of Fig. 3; y

vFig. 2 depicts a vertical longitudinal sectional view through the oven,heating flues, regenerators and single chimney flue, taken on line 2-2of Fig. 1;

Fig. 3 shows a fragmentary front elevational view, partly broken-.awayto reveal a vertical transverse section through the ovens, heating uesand regenerators taken on line 3--3 of Fig.

Fig. 4 is a vertical longitudinal section through the gun brick, richgas burner nozzles, heating iiues and peep holes, taken on line 4-4`ofFig. 3;

Fig. 5 is a similar view through the ducts connecting the heating iiueswith the regenerators, taken on line 5 5 of Fig. 3;

Fig. 6 illustrates a vertical sectional view, taken on line 6-6 of Fig.1, showing the position of the valves insthe gas box when underfiringthe ovens with lean fuel gas;

Fig. 7 depicts a front elevational view of the pusher side of the ovenbattery, showing the integrated gas and air boxes and the gas manifoldpiping:

Fig. 8 depicts a similar view of the coke side of the oven battery,showing the gas manifold pipme:

Figs. 9, l0, 11 and l2 show the details of construction of a single boxfor air and waste gas;

Figs. 13, 14, 15, 16 and 17 show the constructional details of a singlebox for lean fuel gas and Waste gas;

Fig. 18 depicts a perspective view, showing the circulation through thevarious parts of the oven construction when underiiring the oven withrich fuel gas and preheated air;

Fig. 19 illustrates a perspective View, showing the circulation throughthe heating flues, regenerators, air boxes, gas boxes, fuel gasmanifolds and single chimney `flue when underring with preheated leanfuel gas and preheated air;

Fig. 20 is a vertical cross-section through one of the rich gas portsconnecting thel gun bricks with the heating flues, taken on line 20-20of Fig. 4; and

Fig. 21 is a vertical cross-section through the air and lean gas portsconnecting regenerators with heating flues, taken on line Zi-ZI of Fig.5.

Broadly stated, the present invention relates to a process for coking abroad, fiat layer of carbonaceous material in a coking chamber, whereinit can be sealed against the admission of air. A flow of combustiongases at a temperature sumcient to coke the carbonaceous material isdirected in a plurality of parallel. streams beneath the sole of saidchamber and transversely thereto. 'I'he flow of combustion gasesoriginates beneath andalong one half of a single side of the chambersole, flows across the oven underneath said sole, and finally flows backto the same side of the sole and at the other half of saidside. The flowiis alternately reversed to provide substantially uniform coking of thecarbonaceous material. The process can be satisfactorily carried out ina rectangular broad coke oven heated with aplurality of short, parallelheating ilues located beneath the floor of the oven and Placedtransvers'ely of the oven, all interconnected at one side of the oven bya passage running its entire length. A dual heating system adapted' tofurnish either lean or rich 'fuel gas for combustion in the heatingiiues is provided, and means are incorporated in the oven structure forreversing the flow through the heating system of preheated lean fuelgas, vpreheated air, and waste gas, using valves upon a single side ofthe oven battery and using a single chimney flue continuously. Thiscirculation is maintained by the use of unit gas and air boxes, each ofwhichvis divided into two passages which are used simultaneously and inalternate succession either for air and waste gas or, alternatively, forfuel gas and Waste gas. The heating system may be said to be dividedinto two sections, the hot gases flowing in them in opposite'directionsand each section being pro#s vided with two parallel verticalregenerators. rl'hese regenerators have spacious, chamber-like passagesboth above and below the checkerbrick, giving the gases an opportunitytospread or mushroom out before passing through anclthus increasing thetime of contact and aording more effective heat transfer. Eachregenerator is constructed and arranged to preheat either air or leanfuel gas and, on alternate reversals, to recover the heat from wastegas. The improved oven is so designed that it may also be used forunderring with rich fuel gas. When rich fuel gas is used, allregenerators are employed alter" nately for preheating air forcombustion and for recovering heat from hot waste exit gases.

A coke oven suitable ior carrying out the process of the invention willnow be more fully described to those skilled in the art, reference beinghad to the accompanying drawings illus trating a preferred embodimentthereof. Similar reference characters denote corresponding partsthroughout the various ligures.

Referring, now, more specifically to Figs. l to 3, it is readilyobserved that the oven battery of my invention comprises a plurality ofdomed, rectangular, broad coking chambers H-i havm ing charging holesH-2 in their roofs. Beneath each of these chambers are arranged in transverse position a plurality ci parallel heating fiues, one half of whichare denoted by reference character i; the other half are denoted byreference ligure 2. All of these heating fiues are con nected at one endthereof with a common longi tudinai ue 3. Heating iiues i are connectedat the other ilue end with ducts t and E and, through these ducts, toregenerators R-S and R.-i, respectively. Heating ues 2 are connected atthe other end thereof with ducts 6 and l, and, through these ducts, toregeneratorsl R-i and BF2, respectively. This end of the heating iiues,where the connecting ducts to the regenerators open into the dues toform a Y-junction, is the firing end, and burning means is hereprovided. The oven is4 provided with valvular means, such as the twocombination valve or damper boxes A--i and A-2, a preferred constructionof which will be described infra. Regenerator Rf-i is connected by a passage P-2 with valve box A--i and thence by a passage P- (see Figs. 9 andl0) with a single chimney flue C. Passage P-Z runs underneath the entirelength of regenerator Rf-i, and the whole top of the passage is open tothe mushrooming chamber under the checkerbrick of the regenerator.

separated by a division wall W-I from a passage P-I which is closed o atthis section and does not communicate with this regenerator. It isimportant that cross-leakage between these two passages be prevented,and to that end passage P-I is encased in an impermeable sleeve,prefer.- ably of 1/.1 inch alloy steel or the like, which is made ofheat and corrosion resistant material,-

However, passage P-Z occupies v1 only half the width below regeneratorR-I being such as nickel-chromium steels or chromium steels or the like.Passage P-I runs the full length of the oven, being closed oi asdescribed under regenerator R-I but open at the top for that half of itslength under regenerator R-2, where it communicates directly with themushrooming chamber under the checkerbrick. Regenerator Rf-Z isconnected by this passage to valve box A-i and through this valve boxand passage P-5 to the single chimney ue C. Regenerator R-3 is connectedby a passage P-4 to valve box A-Z and through this valve box and apassage P-- to chimney iiue C. Passage P-4 is similar in construction topassage P-2 described supra, and it bears exactly the same relationshipto regenerator R-S that passage P2 bears to regenerator R--i. Likewise,a passage P-3, encased similarly to passage P-i. runs under regeneratorR-t and communicates with'.

regenerator Rf-f'l in exactly the same manner that passage P-i connectswith regenerator R-2. A division wall W-2v separates passages P-- andP-fi from each other. Regenerator R--l is connected through the passageP- to valve box A-2 and thence by passage P-B to chimney flue C.

A lean fuel gas manifold G-i runs the length of the pusher side of theoven battery and is connected by risers G-2i and (Zi-22 to valve box.fi-2 on each oven. Rich gas manifolds C-3i and G-32 run the length ofthe oven battery on opposite sides thereof and connect through valvesV-Iil (shown diagrammatically) with risers (5k-i3, which lead into gassupply channels in the division walls between the ovens.

The valves in the gas connection pipes (2t-ii are ,K

connected in the usual manner by a cable to the drum of a standardreversing mechanism (not shown), or other valve-actuating means can beemployed;

A reference to Figs. i and 5 will afford those skilled in the coke ovenart a ready understanding of the construction at the ring end of thetransverse fiues into which the gas supply channels lead. Extendingcrosswise of the oven battery in the division walls between the ovens.

p which is to say at the iiring end of the transverse heating iiues, aretwo gas supply channels of gun brick il and i2. These gun brick are notconnected at the point of-meeting on the center line of the ovenbattery, but are `separated by a division wall W--3. The gun brick ii onthe pusher side of the battery is connected through the valve controlledconnection pipe G-i with gas manifold pipe G-3 i, while the gun brick i2on the coke side is connected through the valve controlled connectionpipe G-I with gas manifold pipe G-32. The gun brick is connected by aseries of ducts I3 to each of heating ues i, and similarly channel l2connects with heating ilues 2 by ducts Iii.

Within ducts i3 and M are orifice gas nozzles N-i. Above them, runningfrom the top of the heating ilues to the top of the oven, are openingsN2through which a special tool may be employed either to replace thesenozzles with other nozzles or to regulate the flow of preheated air (orlean gas, when used) from ducts 4,15, 6 and 'I into heating flues I and2. A detail of the Y-iunction point of ducts 4 and 5 into flue i isdepicted at Fig. 21. Each Y-junction from the ducts above theregenerators into the heating lues is provided with a pair of slidingbricks N`3, the position of which determines the size of the port andhence regulates the flow.

shaft extends the width of the passage, and one end of it passes throughthe left side of the passage. The shaft is suitably mounted in the sidesferred, however, to use the two types of valve boxes illustrated,respectively, by Figs. 9 to 12 and Figs. 2, 6, and 13 to 17. It is to beobserved that the preferred form of valve box adapted to handling airand waste gas, as illustrated in Figs.

suitable metal casting, as of a corrosion-resistani-. material, such asalloy cast iron of the 9 to 12, has a single housing A-i, preferably achromium or the chromenickel type or the like.`

Both right and left hand boxes are required, the boxes being identicalin, design but mirrored as to each other in assembly, as shown in Fig.7, and they are operated by dierent cables. Moreover, each box isdivided by a wall W-t into two substantially equal and entirely separatehalves.

, Except that the parts are positioned enantiomorphically. the valves ordempers and the means for operating them in each half are identical. Forthis reason, only one half will be described. On the left hand side ofthe box, there is Y mounted at the top thereof an air inlet damper aseat upon which removable air-regulating bars f B can be placed. Thevalve V-,-i is supported by a valve stem V--i b which is keyed to arotatable shaft S-L The shaft is held in position by a suitable sleevemounting lvl-i which is rigidly fastened to the housing. i

Inside the valve chest thus formed, there is mounted a waste gas exitdamper or valve il-22, the face V-ti of which is adapted to make asubstantially air-tight contact with the seat if-22 oi a port V-tii atthe bottom of the box. This port forms the upper end of passage or ductP-b which connects the valven chamber with the chimney fiue C. The valveV--ii is supported by valve stem tf-2b, which is keyed to a rotatableshaft S-t. This shaft is mounted in a suitable sleeve mounting M-2,which is rigidly fastened to valve box ifi-i, and the shaft extendsthrough the left side of and outside the box. Y

Keyed to one one of rotatable shaft S-i is the fulcrum of a bell crankL-i. The bell crank has a straight arm which is connected by a suitableconnection to a cable C-i which runs along the entire battery of ovens.The other arm of the bell crank. is curved outward and over the edge ofbox A-i and at its end it connects with an' adjustable rod L-i. This rodcomprises three parts: the upper part L-Zi, connecting at the upper endthereof with the bell crank and with its lower end'threaded; aturnbuckle L22, which is screwed onto the threaded end of lli-2 i and alower part L-ts, having either a swivel or a thread at its upper endadapted to coact with L--it and connected at its lower end to a leverLever L-t is keyed to the end of shaft S-r which protrudes from the sideof the valve box. The turnbuckle is adjusted to make rod L-t of suchlength that air valve V-i is open when waste gas damper V-Q is tightlyclosed, and vice versa.

In passage P--5 there is a rectangular plate damper V--s adapted toclose off the passage in any degree required. It is mounted on a shaftS-t which forms its longitudinal' axis. This of passale-P-b.l To the endof shaft 8 3 which protrudes from the side. a quadrant' Q is attachedThe reversing mechanism for operating the` i airv and waste gas dempersis not shown, as

those skilled in the art, are familiar with the construction andoperation. It may be briey described as consisting of a motor drivendrum around which the cable C-i is wound. A time cloclr, which is setfor nxed reversal periods, is adapted to make the necessary electricalcontacts required for starting and stoppingv the motor and for shiftingthe gears which change the direction of travel of cable C--i.` The cableis adapted for alternately opening and closing all dampers as required.As each valve box is divided into left and right hand halves, the sametravel of cable C-i which opens air valve V-i and closes waste gas valveV-i o n the left side of the box closes air valve V-iR and opens wastegas valve V-QR on the right side of the box. Similarly, cable @-2(seehig. 7) is adapted for alternately opening and closing the valves onalternate air-waste gas valve boxes i-i, which, though identical indesign and operation with those operated by cable C-l, are mirrorassemblies of them.

The valve box which I prefer to use for handling lean fuel gas and wastegas is very similar .in design and construction to the air and waste gasvalve box just described. Likewise, both right vand left hand boxes,operated by different cables, are provided, as with the air-waste'gasvalve boxes. Each box, too, has a single housing A-t, preferably of thesame material as that enantiomorphic haves by wall VV- 5. The samesystem of levers and shafts is used as described supra, so that, exceptfor a few salient (lider ences, no detailed description will be givenhere. The reference characters in Figs. 13 to 17 have been kept the sameas far as possible, merely using a different initial letter, wherenecessary for identication. Also, Figs.- 13 to 17 correspond to Figs. 9to 12 in that they depict the positions of a fuel gas-waste gas valvebox and an airwaste gas valve box, respectively, for the same oven (herethe fourth from the left, for example, in Figs. 3 and 7) at" the samemoment of time.- For this reason, the construction and. operation of thebox will be described with respect to cable C2, though it will beappreciated that alternate fuel gas-waste gas valve boxes A--Z arecontrolled by cable C--i. Cables C-i and C-Z travel in oppositedirections at any time interval, so that, for an individual oven, wherecable C--i operates the air box, C-2 operates the gas box, and viceversa.

Referringlonly to the leit hand half of the valve box, air inlet valveor damper D-i is mounted in a position similar to that of valve V--i inhousing A-i. The valve stem D-i5 is mounted with a set screw D-IB,however, adapted to key or unkey the stem to shaft S-I. By this device,the air inlet valve D-i is adapted to be governed by or freed from themovements of cable C-Z (as transmitted by bell crank L`i and shaft S-i), depending upon whether rich gas or lean gas is used. Thus, whenusing lean gas, valve D-i remains closed. Cable C--2 is connected toshaft S2 of valve box A-2 by means similar to the means connecting cableC-I to shaft S-Zoi box A-I,

'I3-25 and D-et, respectively, of two valves D--2 and D-. Valve D-2 isthe waste gas exit damper, and its face 12B-2l is adapted to make asubstantially air-tight contact with the seat D-ZZ of port D-il.Similarly, the face D-fli of lean gas inlet valve D-tl is adapted tomake a substantially air-tight contact with the seat D-l-' of port i3-438. 'Ihe length and shape of the arms of the bell crank are soconstructed that travel of cable C--Z to the left closes valve D--2 andopens valve D-l, while travel to the right ,closes valve D- and opensvalve lli-2. In the righthand half of the valve box, since the leversare reversed, travel of cable C-Z to the left opens the waste gas valveand closes the lean gas valve, whereas travel to the right has theopposite eect.

As in passage vP-tl, a' rectangular Vdampei D--S is placed in passageP-d and is adapted to close off this passage, as required.

The reversing mechanism for operating the lean gas and waste gas dempersis, of course, the same as briefly described in connection with the airand waste gas dampers oi the other box. There is also a valve D-b (seealso Fig. '7) in each riser, G-2I and (Ef- 22, from the lean gasmanifold G-i, and this valve is adapted to shut oi the gas supply and toprevent leakage into valve box A2 when rich gas is being used forunderlring,

Reference to Figs. l and 7 will disclose a. valve D-E in the lean gasmanifold G-I. Valve D- is used momentarily during each reversal periodin order completely to shut o the lean gas from manifold G-l untilreversal has taken place. The closing or this valve prevents any leangas from flowing into valve box A- through G-2I or (3p-22 and on out tothe chimney ue through passage P-e while both the lean gas inlet valvesand the waste gas outlet valves are partly open during the process ofreversing.

Valve D-B may be of any suitable type and may be operated by anyappropriate means, as by a solenoid electrically connected in the usualmanner with the clock-operated reversingl valve mechanism.

In the operation of the oven as an entire unit, oven doors H-3 and H-ilare closed and sealed air-tight, as may be seen from Fig. 2. Coal ischarged through the charging holes H-Z in the top of the ovensee alsoFig. 3), and the coneshaped piles are levelled ofi in the usual mannerby a levelling rod K, introduced through `a small door H-I in the pusherside oven door. The charging hole covers H-5 are replaced and sealedair-tight. Fuel gas .is then burned with preheated air in the uesunderneath the coking chamber to provide a substantially uniform cokingtemperature for the entire area of the oven sole upon which .the coalcharge is supported. As is Well-known by those skilled in the art, thecoking temperature varies depending upon whether low or highcarbonization is desired. Thus, a suitable temperature for'low coking,such as about 600 to about '700 C. to a suitable temperature forhighcoklng, for instance, about 1,150

to about 14:50o C., can be successfully used. Reversal periods ofsuitable duration are employed. as those skilled `in the art will know,and a reversal about every l5 minutes has been found to givesatisfactory results when underflring with rich fuel gas and preheatedair. When preheated lean fuel gas is burned in the flues with preheatedair, a reversal of about 30 minutes duration gives more satisfactoryresults. An ofitake pipe H-ii at the end of the oven provides an outletfor the gases evolved during coklng, and these pass to the by-productplant. When the coal is coked, oven doors H--S and H-4 are removed, andthe coke is pushed in the customary way.

The operation of this improved broad coke oven will now be describedparticularly in conjunction with Figs. 18 and 19, which illustratediagrammatically the flow of gases through the several flues, ducts,regenerators, dampers and valves, for the convenience of those skilledin the art.

When using lean fuel gas (Fig. 19), and assuming that regenerators 1?.-2and R--l are being heated by the outgoing gases of combustion, waste gasdamper D2 (see also Fig. 13) on the left side of valve box A-2 is open,and fuel sas inlet valve D- on the same side of the box is closed,permitting a flow of waste gas from regenerator Rf-t alon'g passage P-3and through the left side of the valve box A-2 into chimney flue C.Likewise, waste gas damper,

V-i-ZR. (see also Fig. 9) in the right side of valve box A-l is ppen,and air inlet valve V-IR on the same side of the box is closed,permitting l Waste gas to flow from regenerator R-2 along passage P-iand through the right side of valve box A-I into chimney flue C.

The lean gas to be preheated enters through valve D-Rin the right sideof valve box A-2, waste gas damper D-2R on that side being closed. Thegas flows along passage P--4 into the mushrooming chamber underregenerator Y R-S, where it spreads out, and then ascends uniformlythrough the hot checkerbrick in the regenerator, passing into ductsSimilarly, the air to be preheated enters through valve V-I on the leftside of valve box A-I, waste gas damper V-2 on that side being closed.The air then flows along passage P-Z into the spacious chamber belowregenerator R-I, Where it mushrooms out, and then uniformly up throughthe hot checkerbrick. The heated air passes into the ducts E and, at thedebouchment points of ducts l and 5 into heating fiues I, meets the hotfuel gas. (This point is the same as that for ducts t and 'I and ilue. 2and is shown in detail at Fig. 21.) It will be observed that provisionof relatively large gas spaces above and below the regenerators permitsthe gas (here. air) to spread out before entering the checkerbrick andthus slows down its passage through the regenerators, giving improvedheat transfer. This preheated air is delivered at the firing end of eachheating flue I .in an amount suitable 4,for the combustion oi' Athepreheated lean gas delivered there, and gas and air are mixed in theheating fiues, so that combustion takes place simultaneously in allheating nues I.

It is obvious from the construction of the heating fiues, as detailedsupra, that each heating ue I will have its own ame shooting across thewidth of the oven, a very short distance to travel. The products ofcombustion from heat- 4ing fiues I enter longitudinal flue 3 and,through 2,309,959 'nue a, are introduced into the remaining heat- :ngnues 2. At the other end of fides 2, the volume of waste gas is dividedbetween ductsy 6 and I and flows downward into th`e mush.- rooxningVchambers above R2 and R4. These waste gases descend uniformly and atreduced velocity through the regenerators. giving up most of their heatto the checkerbrick,` and ov into passages P-I and P-3,' whence they goto the stack, as above described. Thus, it will be observed that theoven of the invention is constructed in such manner that the gases whichare being heated ascend and the gases which are giving up heat descend,whereby maximum heat economy and uniformity of operation are assured.

'Upon reversal of the draft, with preheated gas and air entering heatingflues 2 through ducts 6 and ducts 1, respectively, the flames burnsimulclosed. as they remain during operation with lean gas. r.

The operation of the lean gas valve boxes is clear from a scrutiny ofFigs. 13 to 17. As shown,

5 cable C-2 has traveled to the right, moving the taneously in flues 2,at the other end of the oven.-

'In this way, first one half of the oven and then the other is subjectedto the highest temperature, so that the heat furnished throughout a fullcycle is substantially uniform for the entire oven length. The center isobviously under exactly the same conditions as are the ends, so thatthere can be neither overcoking at the ends of the oven nor undercokingyat its center. Besides that, no cold black spots are possible in theshort transverse flues. y

When the regenerators R-Zand R4 are raised to the temperature necessaryfor preheating the lean gas and air, the directions of iiow are changedby opening gas inlet valve D--4, air valve V-IR, and waste gas dampersD-ZR and V-2, while closing lean gas valve D-R. air valve V-I, and wastegas valves D-2 and V-2R. Air then enters through valveV-IR and flowsthrough passage P -I and up through regenerator R-2 into ducts l.Leangas enters through valve D4 and ows through passage P-3, up throughregenerator R-d, and into ducts 6. After burning in flues 2, the wasteproducts ow down through regenerators R--I and R- and out the dampersD--2R and V2 into straight arm of bell crank L-Iin the same direction.As the valve stem D-I5 has been unkeyed from the shaft S-I to which thebell crank is keyed, there is no movement of air valve D-I, whichremains tightly closed. The curved arm of bell crank L-I has been movedupward in an arc and has pulled up upon adjustable rod L-2, which has inturn raised lever L--3. Lever L-S has turned shaft S--2, to which it iskeyed, and this in turn has turned bell crank L-l.

The movement of bell crank L-4 has b oth closed y lean fuel gas valveD-lI and opened waste gas valve D-2. In similar but reverse operation.the travel of cable C-2 to the right has opened gas inlet valve D-AR.and closed waste gas damper D-ZR. The travel of the cable to the lefthas the opposite effect.

Stack draft is used for drawing 4air into the regenerators and forremoving the gases of combustion. The stack draft for each separate cokeoven is regulated by the position of the plate dampers V-3 and D-3,which are held in position in the passages to the chimney iiue byquadrants Q. The air valves are equipped with airregulating bars B, asmentioned supra. Bars B are removable, and the volume of air to eachregenerator is controlled by the size and number of removable bars usedto regulate the size of the opening into the body of the box. Inproviding lean gas for heating the ovens, the fuel gas, under a slightand constant pressure, is conducted through supply manifold G--I andinto risers G-2I and G--22 (see also Fig. 3).

-Its supply to the burners is regulated by brick y using rich fuel gasand preheated-air will be best the single chimney flue C.

The operation of the air valve boxes is clear from Figs. 9 to 12. In theposition shown, cable C-I has traveled to the left, moving the straightarm of .bell crank L-I in the same direction. The bell crank has turnedshaft S-I to which it is keyed. This movement of the shaft has raisedvalve V-I from its seat. The curved arm of bell crank L--I has beenmoved downward in an arc and has pushed down upon adjustable rod L-Z,which has in turn depressed lever L-3. Lever L-3 has turned shaft 8 2,to which it is keyed, and this in turn has lowered damper V--2 into itsseat. In similar but reverse fashion, the travel of cable C-i to theleft has opened damper V-2R and closed air inlet valve V-IR. Thesepositions are illustrated also by the seventh valve box (the air box forthe fourth oven) in Fig. 7, which shows the arrangement cf the boxeswhen cable C--I has traveled to the left and cable C-2 has traveled tothe right. It will be seen that each air box has one air valve open andthe other closed, the open valve being left or right depending uponwhether the box is operated by cable C-I or C-2. This order is of coursereversed by reversal of travel of the cables. It ls also to 4be notedthat bothair valves D-I and D-IR on the lean gas valve boxes are brickIl.

understood from Fig. 18. When using rich fuel gas andpreheated air,`allconnections are the same as described for lean fuel gas, except that therich fuel gas is not preheated and that all regenerators are usedalternately for either preheating air or for being heated by the hotwaste gases. Assuming that regenerators R-2 and R-d are being heated bythe outgoing hot gases of combustion, air to the preheated enteisthrough dampers V-I and D-IR andvs introduced by means of passages P-2and P-d, respectively, into the regenerators R-I and llt-3, in which theair ascends. After having passed through the regenerators, the preheatedair is brought into heating flues I through ducts t and 5. The rich fuelgas is introduced through a gas manifold (3i-3l and a riser G--fl intogun The gas passes through burner nozzles N-I in du'cts I3 to heatingflues I, where it mixes with the preheated air from ducts and 5 and isburned. The products of combustion from heating ues I enter commonconnecting flue 3 andare divided again among ilues 2. The volume ofwaste gas flowing through ilues 2 is divided again between flues 6 and'I and ows downward through regenerators Rf-2 and R--, along passage P-Iand P-3, and out of the valve boxes into chimney flue C.

During the alternate reversal` regenerators RI and R-3 are being heated,and the air is being preheated in regenerators R-2 and Rf-. During thisreversal, the rich fuel gas is shut off from gun brick gas supplychannel II and ducts I3 and flows, instead, through gas manifold pipeG--32, gun brick I2 and nozzles N-I in ducts I4. Combustion now takesplace in heating 4flues 2, the waste gas flowing through flue 3 outflues I into regenerators R-I and R-3,

The operation of the air valve boxes is, of course, exactly the same aswhen lean gas is being used, as detailed in connection with Figs. 9 to12, supra. The valve boxes A-2, employed for lean gas when it is desiredto use lean gas for fuel, are now converted into additional air boxes byadjusting set screws D-I6 and D-IER on each box (see Fig. 13), thuskeying the air valves D I and D-IR to the lbell cranks L-I and L-IR. Inthis way, the travel of cable C-2 to the right opens air valve D-IR justas C-I, traveling to the left, opens air valve V-I, and air passes toboth regenerators R--I and R--3 to be preheated. No lean` gas is used,of course, and hence the opening of valve D-4R leading to the lean gasmanifold (described supra in connection with Figs. 13 to 17) has noeffect on the system, the manifold being sealed off by the closing ofthe valves D-5 in the risers. The travel of cable C-2 to the right openswaste gas valve D-2 in box A-2, just as in operation with lean gas.Travel to the left of thc cable reverses the operations.

It will be appreciated by those skilled in the coke oven art from theforegoing description that a convertible broad coke oven constructed tocarry out the process of my invention possesses extreme simplicity ofoperation. Furthermore, it is to be noted that the ease with which theoperator can change over from lean gas, such as producer or blastfurnace gas, to rich gas, such as coke oven gas, or vice versa, in thisconvertible broad coke oven has never before been even approached by theprior attempts or proposals. The foregoing, with the other advantageousfeatures described herein, gives my novel and improved processcombination a flexibility of operation never before attained by the cokeoven art.

It will also be appreciated that, according to my novel process, it ispossible to produce a coke which is far more suitable for domesticpurposes than was the coke produced by the processes employed in thehigh, narrow ovens of the prior art. The pressure in the plastic massresulting from a deep, narrow charge materially affected the cokestructure, so that a hard, dense, slow-burning coke having a close cellstructure was necessarily produced. Such coke was really only suitablefor metallurgical purposes, although the surplus was sold for domesticuses. Coke for domestic use should have an open, free-burning cellstructure, and this type of coke can be made by my process. Leveling offthe `coal charge in an oven using my process over the entire horizontalheating surface gives a thin layer of about to about 18 inches in depthspread evenly over a surface about 35 to about 45 feet long and about 8to about 12 feet wide, The free flow of hot, evolved gases through thethin coal charge and the low pressure to which the coal in the plasticstate is subjected create entirely different carbonizing conditions fromthose prevailing in the high, narrow ovens, An open cell structureresults, and, in addition to the fact that a differentmoleculararrangement of the 754 coke structure is developed, thecarbonizing reaction is accompanied by less than the amount of crackingof by-products which resulted from contact with the hot, verticalsurfaces of the prior art. Thus, the broad, fiat oven herein describedin connection with my improved process can be operated to leave asuitable volume of volatile matter in the coke to insure the freeburningproperties desirable in domestic coke. It will, of course, be understoodthat an appropriate mixture of coals can as readily produce a high grademetallurgical coke by my novel process, so that my process has the greatadvantage of being adaptable to the production of either domestic ormetallurgical coke.

Although the present invention has been disclosed in connection with apreferred oven construction for carrying out the same, variations andmodications of this construction may be resorted to by those skilled inthe art, without departing from the principles of vthe invention.

Thus, while a preferred arrangement of valvesv has been described and apreferred reversing mechanism for their operation has been indicated,

those skilled in the coke oven art will readily perceive that otheroperative valvular means could be substituted for my arrangement, andthatV 'other valve-actuating means could be used with satisfactoryresults. It will also be observed that, while I have preferred to employa regenerative system under each oven which comprises two sets ofvertical regenerators with each set comprising two regenerators as asingle parallel pair, sets of more than one pair. could besatisfactorily used with relatively minor alterations and @.djustments.Moreover, while I have described my invention particularly withreference to the coking of coal, it will be readily understood that itis as easily adaptable to the coking of any carbonaceous material, suchas peat, tar, lignite, pitch, culm waste and other low grade coals, fueloil, bunker oils and other petroleum products, and the like. I considerall of these variations and modifications as within the true spirit andscope of the present invention, as disclosed in the foregoingdescription and defined by the appended claims.

The `present application is a division of my copending application,Serial No. 301,173, filed October 25, 1939, and entitled Broad'cokeovens, now Patent No. 2,234,172.

I claim:

1. The process of coking carbonaceous material in a coking chamber of along, rectangular oven broader than its height, which comprisesintroducing carbonaceous material into said coking chamber; spreadingsaid carbonaceous material onto the sole of said coking chamber in alayer that is thinner than its width and length; sealing said ovenagainst the admission of air; originating at predetermined spaceintervals along a portion of one side of the sole of said coking chamberand transversely thereof, a flow of hot combustion gases to furnish heatat a temperature sufficient to coke said carbonaceous material on the'sole of said coking chamber; conducting said ilowof hot combustiongases under a portion of the area of the sole of said coking chamber ina plurality of substantially parallel unidirectional individual streams,said streams having their ends at predetermined space intervals along aportion of the side of the sole of said coking chamber opposite to theside where the flow of hot combustion gases originated; merging the endsof -said plurality of substantially parallel 2,309,959 I unidirectionalindividual streams to combine the flow of hot combustion gases into asingle stream underneath the side of the sole of said coking chamberopposite to the side where the flow'of hot combustion gases originatedand substantially perpendicular to said plurality of substantiallyparallel unidirectional individual streams; dividing the flow of hotcombustion gases in said single stream into another plurality ofsubstantially parallel unidirectional individual streams of hotcombustion gases under the remaining portion of the area of the sole ofsaid coking chamber and transversely thereof, said streams having theirends at predetermined space intervals along the remaining portion of theside of the sole of said coking chamber where the iiow of hot combustiongases orig'niated and wherein the direction of flow is opposite to thedirection of ilow in the rst plurality of substantially parallelunidirectional individual streams,'where by substantially the total areaof the sole of said coking chamber can be sufciently heated for fullcoking; alternately reversing the directions of flow of hot combustiongases in said single stream\ and said pluralities of substantiallyparallel individual streams,whereby uniform heating conditions oversubstantially the total area of the sole of said coking chamber can beattained and whereby hot spots and partly undercoking and partlyovercoking of the carbonaceous material on the sole of said cokingchamber are avoided; and continuing said alternate reversals until theentire volume of the layer of carbonaceous material is fully coked,wherebycarbonaceous material is coked substantially uniformly.

2. The process of coking 'carbonaceous material in a coking chamber of along rectangular oven broader than its height, which comprisesintroducing carbonaceous material into said coking chamber; spreadingsaid carbonaceous material onto the sole of said coking chamber in alayer that is thinner than its Width and length; sealing said ovenagainst the admission of air; originating at predetermined spaceintervals along a portion of one side of the sole of said coking chamberandl transversely thereof, a flow of preheated combustion air;conducting said iiow of preheated combustion air under a portionA of thearea of the sole of said coking chamber in a plurality of substantiallyparallel unidirectional individual streams, said streams having theirends at .predetermined space intervals along a portion of the side ofthe sole of said coking chamber opposite to the side where the ilow ofpreheated combustion air originated; merging the ends of said pluralityof substantially parallel unidirectional individual streams to combinethe flow of preheated combustion air into a single stream underneath theside of the sole of said coking chamber opposite to the side where theflow of preheated combustion air originated and substantiallyperpendicular to said plurality of substantially parallel unidirectionalindividual streams; dividing the ow of preheated combustion air in saidsingle stream, under the remaining portion of the area of the sole ofsaid coking chamber and transversely thereof, into another plurality ofsubstantially parallel unidirectional individual streams of preheatedcombustion air, said streams having their ends at predetermined spaceintervals along the remaining portion of the side of the sole of saidcoking chamber where the flow of preheated combustion air originated andwherein the direction of flow is opposite to the direction vof. ow inthe r'st 75 plurality vof substantially parallel unidirectionalindividual streams; introducing rich fuel gas at the point o! origin ofeach stream in the rstmentioned pluralityvof substantially parallelunidirectional individual streams of preheated comdirectional individualstreams, merge intoA a single flame longitudinally of said cokingchamber in the single stream. and travel in a direction that is oppositeto the initial direction and transversely of said coking chamber in thesecondmentloned plurality of substantially parallel unidirectionalindividual streams, to produce hot combustion gases to furnish heat at atemperature suflicient to coke said carbonaceous material on the sole ofsaid cokingchamber, whereby substantially the total area of the sole ofsaid coking chamber can be sufliciently heated for full coking by richfuel gas burning with preheated combustion air'at a single side of thecoking oven; alternately reversing the directions of flow of preheatedcombustion air in said pluralities of substantially parallel individualstreams and in said single stream, and alternately introducing rich fuelgas at the point of origin of each stream in a pluralityof substantiallyparallel unidirectional individual streams of preheated combustion airupon reversal of the flow of preheated combustion air therein, wherebyuniform heating conditions over substantially the total area. of thesole of said coking chamber can be attained and whereby hot spots andpartly undercoking and partly overcoking of the carbonaceous material onthe sole of said coking chamber are avoided; and continuing saidalternate reversals until the entire volume of the layer of carbonaceousmaterial is fully coked, whereby carbonaceous material is cokedsubstantially uniformly.

3. The process of coking carbonaceous material in a coking chamber of along rectangular oven broaderthan its height, which comprisesintroducing carbonaceous material into said coking chamber; spreadingsaid carbonaceous material onto the sole of said coking chamber in alayer that is thinner than its width and length; sealing said ovenagainst ,the admission of air; originating at predetermined spaceintervals along a portion of one side of the sole of said coking chamberand transversely thereof, a ilow of preheated combustion air; conductingsaid ilow of preheated combustion air under a portion of the area of thesole of said coking chamber in a. plurality of substantially parallelunidirectional individual streams, said streams having their ends atpredetermined space intervals along a portion of the side of the sole ofsaid coking chamber opposite to the side where the flow of preheatedcombustion air originated; merging the ends of said plurality ofsubstantially parallel unidirectional individual streams to combine theflow of preheated combustiony air into a single stream underneath theside of the sole of said coking chamber opposite to the side where theflow. of preheated combustion air originated and substantiallyperpendicular to said plurality of substantially par- '10 I i i allelunidirectional individual streams; dividing v`the flow oi' preheatedcombustion air in said single stream, under the remaining portion ot thearea of the sole or said coking chamber and transversely thereof, intoanother plurality of substantially parallel unidirectional individualstreams of preheated combustion air, said streamsA having their ends atpredetermined space intervals along the remaining portion oi the sideofthe sole of said cking chamber where the iiow of preheated combustionair originated and wherein. the direction of iiow is opposite to thedirection of iiow in the rst plurality of substantially parallelunidirectional individual streams; introducing preheated lean fuel gasat the point of origin of each stream in the inst-mentioned plurality ofsubstantially parallel unidirectional individual streams of preheatedcom-bustion air; burning said preheated lean fuel gas in said`first-mentioned plurality of substantially parallel unidirectionalindividual streams, said single stream, and said second mentionedplurality of substantially parallel unidirectional individual streams ofpreheated combustion air to propagate therewith a plurality ofsubstantially parallel flames that travel in one direction andtransversely of said coking chamber in said mst-mentioned plurality orsubstantially parallel unidirectional individual streams, merge into asingle ame longitudinally of said coking chamber in the single stream,and travel in a direction that is opposite to the initial direction andtransversely of said coking chamber in the second-mentioned plurality ofsubstantially parallel unidirectional individual streams, to produce hotcombustion gases to furnish heat at a temperature sufllcient to cokesaid carbonaceous material on the sole of said coking chamber, wherebysubstantially the total area of the sole of said coking chamber can besufficiently heated for full coking by preheated lean fuel gas burningwith preheated combustionl air at a single side of the coking l oven;alternately reversing the directions of ilow of preheated combustion airin said pluralities of substantially parallel individual streams and insaid single stream, and alternately introducing preheated lean fuel gasat the point of origin of each stream in aV plurality of substantiallyparallel unidirectional individual streams of preheated combustion airu'pon reversal of the flow of preheated combustion air therein, wherebyuniform heating conditions over substantially the total area of the'soleof said coking chamber can be attained and whereby hot spots and partlyundercoking and partly overcoking of the carbonaceous material on thesole of said coking chamber are avoided; and continuing said alter-`nate reversals until the entire volume of vthe layer of carbonaceousmaterial is fully coked; whereby carbonaceous material is cokedsubstantially uniformly.

4. In the process of coking carbonaceous material in a broad cokingchamber of a low, long, rectangular oven comprising introducingcarbonaceous material into said broad coking chamber, spreading saidcarbonaceous material onto the sole of said broad coking chamber in alayer that is thinner than its width and length,

sealing said oven against the admission of air, and establishing a flowof hot combustion gases under the sole `of said broad coking chamber tofurnish heat at a temperature sumcient to coke said carbonaceousmaterial on the sole of said broad coking chamber, the improvement whichcomprises originating at predetermined` space intervals alonga portionof one side of the sole of said broad coking chamber and transverselythereof, a flow of hot combustion gases to furnish heat at a temperaturesuiiicient to coke said carbonaceous material on vthe sole of saidcoking chamber;` conductingl said ilow of hot' combustion gases under aportion of the area of the sole of said broad coking chamber in aplurality of substantially parallel unidirectional individual streams,said streams havingvtheir ends at predetermined space intervals along aportion of the side of the sole of said broad coking chamber opposite tothe side'where the ow of hot combustion gases originated; merging theends of said plurality of substantially unidirectional individualstreams to combine the flow of hot combustion gases into a single streamunderneath "the side of the sole of said broad coking chamber oppositeto the side where the flow of hot combustion gases originated andsubstantially perpendicular to said plurality of substantially parallelunidirec.

tional individual streams; dividing the f low of hot combustion gases insaid single streams under an adjacent portion of the area of theisole ofsaid broad coking chamber and transversely thereof, into anotherplurality of substantially parallel unidirectional individual streams ofhot combustion gases. said streams having their ends at predeterminedspace intervals along a portion of the side of the sole of said broadcoking chamber adjacent the portion where the flow of hot combustiongases originated and wherein @the direction of ow is opposite to thedirection of ow in the rst plurality of substantially parallelunidirectional individual streams, whereby substantially the total areaof said adjacentportions of the sole of said broad coking chamber can besuiliciently heated for full coking; alternately reversing thedirections of ow of hot combustion gases in said single stream and saidpluralities of substantially parallel individual, streams, wherebyuniform heating conditions CHARLES H. HUGHES.

